Protection of methionol against oxidation by oxygen scavenger: An experimental and modelling approach in wine model solution

Protection of methionol against oxidation by oxygen scavenger: An experimental and modelling approach in wine model solution

Abstract

•One mole of methionol is oxidized by half a mole of oxygen.•At 0.12 and 0.02 mmol L−1 of O2, O2 scavenger in PET prevents methionol oxidation.•Methionol oxidation is modelled by a second-order kinetic equation.•O2 absorption by scavenger is modelled and well represented by second-order kinetic equation.•A model allows predicting the methionol oxidation in the presence of O2 scavenger.

The aim of this study was to evaluate the impact amount (1% and 3%) of oxygen scavengers (os) incorporated in a PET matrix on methionol oxidation in model wine solutions with different initial oxygen concentrations. At saturated oxygen concentration, the studied amount of oxygen scavenger did not affect the methionol preservation. In more realistic oxygen concentration of wine (0.117 mmol L−1), methionol was only protected after contact with 3% of oxygen scavenger. For a minimal concentration of oxygen (0.024 mmol L−1), the presence of scavenger slowed down the methionol degradation by 1.2 and 1.9 times for 1osPET and 3osPET respectively. For the strongest oxygen concentrations, a mechanistic model was proposed to predict methionol degradation in relation to scavenger amount. This model based on second order reactions for methionol degradation and oxygen consumption by scavenger fitted well with the experimental data. An improvement of this model has been developed for the low initial oxygen amount.